The present embodiments relate to a local coil for magnetic resonance applications.
In the case of magnetic resonance systems (e.g., imaging magnetic resonance systems), the excitation of an examination subject may be effected with a whole body coil (body coil). The acquisition of excited magnetic resonance signals is achieved by local coils. Local coils enable the magnetic resonance signal to be received with a significantly better signal-to-noise (SNR) ratio than with whole body coils.
The received magnetic resonance signal is to be transmitted to a control and evaluation device of the magnetic resonance system. This transmission may initially be effected by suitable cables (e.g., coaxial cables). However, different approaches for transmitting the magnetic resonance signal such as, for example, via a radio link (e.g., wirelessly) to the control and evaluation device are also known. By way of example, reference is made to U.S. Pat. No. 7,592,813 B2.
One approach for the wireless transmission of the magnetic resonance signal includes digitizing the acquired analog magnetic resonance signal inside the local coil and sending the digital magnetic resonance signal via a radio link with a high data rate to the control and evaluation device. Very high carrier frequencies may be used for the digital data communication to achieve the required data rates. Radio links of this kind have very low ranges. For the actual measurement, this does not represent a problem, since, during the examination, the examination subject (e.g., a person) is located in an examination volume (e.g., a patient tunnel) of the magnetic resonance installation. A receiver arranged in the examination volume and connected to the control and evaluation device may, for example, communicate with the local coil without problems.
This procedure is disadvantageous when it is necessary to transmit data from the local coil to the control and evaluation device, or vice versa, prior to or after the actual examination. This is, for example, important for planning the examination. It is, for example, advantageous for the control and evaluation device to know the nature, position, status, etc. of the local coil used before the actual examination. However, this may not be possible with the systems of the prior art. The control and evaluation device may only be able to acquire details of the corresponding local coils when the local coil is introduced into the examination volume. This is, for example, unfavorable in the case of whole body examinations, with which local coils are attached to large areas of the people to be examined and introduced gradually into the examination volume of the magnetic resonance installation.
The situation is similar when the patient couch may be undocked from the magnetic resonance installation, and the patient is prepared for the examination in the undocked state of the patient couch (e.g., in a side room), and the corresponding information is to be made known to the system as early as this stage via the local coils.